The role a metal ion plays in influencing biochemical reactions is multifaceted. With sulfur-containing proteins, metal coordination often is found. Metal ion interactions also presumably are involved in the catalytic disproportionation of O minus over 2 by the copper, iron and manganese dismutases. In this study, we are concerned with the reaction chemistries of sulfur and selenium containing species and the behavior of manganese-(III) and copper(II) complexes with O minus over 2. In addition to synthesizing metal ion derivatives of ligands containing selenium coordination, dynamic studies in solution will be conducted. Our interest will be directed toward oxidation-reduction properties, metal-ligand bond rupture and stereochemical features. Nuclear magnetic resonance, particularly using 77Se as a probe, will be exploited for many of these studies. The chemistry of selenium itself as related to its biological activity will also be examined. The disproportionation of O minus over 2 into O2 and H2O2 by Jahn-Teller active manganese(III) and copper(II) complexes will be investigated. In particular we hope to mimic the behavior of the superoxide dismutase enzymes to learn more about this very important process which prevents cell degradation by superoxide. Electrochemical and spectroscopic techniques will be employed for these studies.